Made in China? LA saw at least one extra day of smog thanks to pollution crossing the Pacific (Picture: AP)

‘Large quantities’ of pollution from China are wafting over the Pacific Ocean to the United States, a new study has found.

Cities like Los Angeles gained at least one extra day of smog last year from China’s export-dependent factories, scientists have revealed.

Nitrogen oxide and carbon monoxide – as well as acid rain-inducing sulphate from burning of fossil fuels – found in the US have been attributed to China’s industrial growth.

Ironically, the pollution is thought to stem from the worldwide demand for cheap Chinese-manufactured goods, making the environmental and health problems an unexpected side effect haunting US consumers.

Noxious clouds have regularly plagued China’s neighbours, such as Japan and South Korea, in the last 20 years.

However many pollutants – including black carbon, which can contribute to climate change and is linked to cancer, emphysema, heart and lung disease – have travelled huge distances on global winds, known as ‘westerlies’, the report showed.

The research was carried out by a team of American and Chinese scientists and published by the US National Academy of Sciences, a non-profit society of scholars.

Steve Davis, a scientist at University of California Irvine and a co-author of the report, said: ‘We’ve outsourced our manufacturing and much of our pollution, but some of it is blowing back across the Pacific to haunt us.’

The report also said that between 17 and 36 per cent of air pollutants in China in 2006 were related to export production – a fifth of which are linked to US-China trade.